When the 88 keys of a piano, harpsichord, or other keyboard musical instrument, require leveling, a lengthy disassembling process has been required so that a proper-thickness key leveling paper punching could be inserted under each key to compensate for manufacturing margin of error, felt punching compression, and paper punching compression. This process has involved removing the fall board, removing the cheek blocks and key slip from the piano, removing the keyboard musical action—including the key frame and keys—from the cavity behind the fall board (see FIGS. 1a,1b adapted from The Piano Book, by Larry Fine, Brookside Press, Boston, Mass., by permission of Larry Fine), removing the action stack from the key frame, installing clip-on lead weights on the back check at the end of each of the 88 keys, sliding the key frame back into the piano, removing the keys needing adjustment from the key frame, removing the cloth punchings, installing or replacing paper punchings with a proper thickness, and then reassembling. Paper punchings come with at least 8 different thicknesses, and one or more paper punchings that provide a proper thickness are selected to provide leveling for each key to a set height.
The process does not lead to definite results because the clip on weight used may not accurately represent the weight actually imposed by the action. This is because every key has a hammer with a slightly different weight and because the back-rail felt under the back of each key, shown in FIG. 1b, is compressible. Thus, other process steps may also be needed to make further adjustments after all these steps are done. This lengthy process has substantially increased the time for assembling a new piano or a new keyboard and for periodic maintenance of an old piano or keyboard, typically needed every two to ten years. This lengthy process has also been a problem for final adjusting high performance pianos before a concert. Thus, a better system is needed to simplify the process of leveling keys and to provide more certain results, and embodiments of such a system are provided in the following description.